
import copy

## General error handling class.
class PyGraphError(Exception):
    def __init__(self, value):
        self.value = value
    
    def __str__(self):
        return self.value

## To indicate that a ploblem occurred while running any of the GraphViz executables.
class InvocationException(Exception):
    def __init__(self, value):
        self.value = value
    
    def __str__(self):
        return self.value
    
